Centrifugal separator



Dec. 17, 1963 J. JISKRA 3,114,655

CENTRIFUGAL SEPARATOR Filed Nov. 16, 1961 '7 Sheets-Sheet 1 Dec. 17, 1963 JISKRA CENTRIFUGAL SEPARATOR 7 Sheets-Sheet 2 Filed Nov. 16, 1961 mm NM. 5 w m4 J 124a a .K Immh/ls AIIORNEY Dec. 17, 1963 J. JISKRA CENTRIFUGAL SEPARATOR 7 Sheets-Sheet 3 Filed Nov. 16, 1961 W RUE INVENTO'P:

J/MOSLA V J/SKRA Dec- 17, J JISKRA CENTRIFUGAL SEPARATOR 7 Sheets-Sheet 5 Filed Nov. 16, 1961 INVENTOP:

JAROSLAV .7/SKRA BY Z'LLQ 11 ffifl his A 77 ORN E V Dec. 17, 1963 Filed Nov. 16, 1961 J. J ISKRA CENTRIFUGAL SEPARATOR 7 Sheets-Sheet 6 his A HORNE Y Dec. 17, 1963 J. JISKRA 3,114,555

CENTRIFUGAL SEPARATOR Filed Nov. 16, 1961 '7 Sheets-Sheet 7 3A FIG- 9 IIIII/I/II/IIII/I/I/I/ F/G' /0a m: /38 1355 W a =L his ATTORNEY United States Patent 3,114,655 CENIRIFU GAL SEPARATGR Jaroslav Jiskra, Ahvaz, Iran, assignor to Masehinenfahriir Buckau R. Wolf Aktiengesellschaft, Grevenhroich, Germany Filed Nov. 16, 1961, Ser. No. 152,789 22 Claims. (Cl. 127-19) The present invention relates to centrifugal separators in general, and more particularly to a centrifugal separator which not only separates a suspension into a liquid and a solid component but also washes the solid component to remove therefrom all soluble matter as well as any traces of liquid component before the solid component is discharged from the separator.

An important object of the invention is to provide a centrifugal separator of the just outlined characteristics wherein the washing of the solid component occurs in a fully automatic way under the action of centrifugal force and wherein all zones of the solid component are brought into intimate contact with the washing fluid.

Another object of the invention is to provide a centrifugal separator which is especially suited for separating extracted sugar juice into a solid and a liquid component, wherein the washing fluid may be utilized as a means for selectively permitting or preventing contact between the solid component and the washing fluid, wherein the washing fluid may be utilized as a means for selectively permitting or preventing evacuation of solid component from the apparatus, and wherein the entire operating cycle including separation of the suspension into a solid and a liquid component, evacuation of the liquid component, washing of the solid component, and evacuation of the solid component may be completed in a fully automatic way in response to changes in pressure prevailin g in the apparatus.

A further object of the invention is to provide a process for separating a suspension into a solid and a liquid component, and for washing the solid component before the latter is evacuated from the apparatus.

An additional object of the instant invention is to provide a centrifugal separator wherein the friction between the rotary and fixed parts is reduced to a minimum, wherein the washing fluid may be utilized as a means for sealingly coupling certain stationary parts with certain rotary parts of the apparatus, which is constructed and assembled in such a way that the suspension is automatically accelerated to the speed of the rotary parts before any separation thereof into a solid and liquid component can take place, and wherein the suspension may be introduced at a continuous rate while the solid component may be evacuated at selected time intervals to insure that the apparatus will operate with utmost efiiciency.

Still another object of the present invention is to provide an apparatus of the above outlined characteristics which is constructed and assembled in such a way that the intervals at which the solid component is evacuated may be adjusted at will in order to take into full consideration the rate of flow and the pressure at which the suspension is admitted to the apparatus.

With the above objects in view, the invention resides in the provision of an apparatus for separating a suspension into a solid and a liquid component, and which in its basic form comprises a rotary housing or drum having an annular solids-collecting compartment, an annular solids-washing chamber which surrounds the solidscollecting compartment, and preferably annular passage means communicatively connecting the washing chamber with the solids-collecting compartment, this passage means being closable and openable by sealing means which is adapted to permit the solid component separated 3,114,655 Patented Dec. 17, 1963 ice from a suspension introduced into the solids-collecting compartment to penetrate by centrifugal force into the washing chamber to expel the washing fluid contained in this chamber into the compartment whereby the washing fluid comes into intimate contact with all zones of the solid component and removes therefrom soluble matter as well as any traces of liquid component which might be entrapped between the particles of the solid component.

The process of my invention comprises the steps of introducing the suspension at elevated pressure into the solids-collecting compartment whereby the solid component is separated from the liquid component when the apparatus rotates, introducing a hydraulic washing fluid into the washing chamber at a pressure which is higher than the pressure of suspension in the solids-collecting chamber, cornmunicatively connecting the solids-collecting compartment with the washing chamber to permit the entry of the solid component into the washing chamber under the action of centrifugal force whereby the solid component expels the fluid into the solids-collecting compartment and the fluid simultaneously washes the solid component while passing from the washing chamber to the compartment, and periodically evacuating the solid component from the washing chamber. The introduction of suspension into the compartment and withdrawal of liquid component from the compartment preferably take place on a continuous basis whereas the frequency at which the solid component is withdrawn depends on the concentration of solid component in the suspension and on the pressure at which the suspension is admitted to the compartment.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following detailed deseription of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a fragmentary axial section through a horizontal centrifugal separator which embodies my invention;

FIG. 1a is a similar fragmentary axial section through a modified separator whose solids-collecting chamber contains disk-shaped separator elements arranged in planes perpendicular to the axis about which the separator rotates;

FIG. 2 is a fragmentary transverse section as seen in the direction of arrows from the line Il-II of FIG. 1;

FIG. 2a is a similar fragmentary transverse section as seen in the direction of arrows from the line IIa-Ha of FIG. la;

FIG. 3 is a smaller-scale transverse section as seen in the direction of arrows from the line IlI-III of FIG. 1;

FIG. 4 is a greatly enlarged fragmentary axial sectional view of a detail of FIG. 1, showing the manner in which a sealing ring may be supplied with pressure fluid;

FIG. 5 is a similar fragmentary axial sectional view of a detail of FIG. 1, showing the manner in which the flanks of a sealing ring may be secured to a disk-shaped supporting element;

FIG. 6 illustrates a leakproof coupling between a stationary pressure conduit and a rotary nipple of the centrifugal separator;

FIG. 7 is an enlarged transverse section as seen in the direction of arrows from the line VII-VII of FIG. 1;

FIG. 7a is a similar enlarged transverse section as seen in the direction of arrows from the line VIIa-VIIa of FIG. 1;

FIG. 7b is a developed view of fixed and rotary blades which accelerate the suspension before the latter is introduced into the solids-separating compartment of the centrifugal separator;

FIG. 8 is an enlarged axial section as seen in the direction of arrows from the line VIII-VIII of FIG. 1, showing a mercury seal between the hollow drive shaft and the stationary supply pipe which delivers suspension to the separator;

FIG. 9 is an enlarged partly elevational and partly sectional view of a solenoid valve which controls the flow of pressure liquid to a sealing ring, the valve being shown in idle position;

FIG. 9a is a similar view of the solenoid valve in energized position;

FIG. 10 is a plan view of the solenoid valve;

FIG. 10a is a transverse section as seen in the direction of arrows from the line Xa-Xa of FIG. 10;

FIG. 10b is a transverse section as seen in the direction of arrows from the line Xb-Xb of FIG. 10;

FIG. 11 is a fragmentary sectional view of a modified solenoid valve in idle position; and

FIG. 11a is a similar fragmentary sectional view of the modified valve in energized position.

Referring now in greater detail to the illustrated embodiments, and first to FIG. 1, there is shown a centrifugal separator which comprises a housing or drum including a pair of spaced concentric disk-shaped end walls 1, 1a and a circumferential wall in the form of two annular wall members 3, 3a, the latter defining between themselves an annular gap 4. The wall members 3, 3a are of triangular cross-section and are respectively welded or otherwise sealingly secured to the inner sides of the end walls 1, 1a. The end walls are respectively provided with coaxial outwardly extending hubs 1', 1a which are mounted on and are rotatable with a coaxial hollow horizontal drive shaft 2. As shown, the width of the annular gap 4 diminishes radially outwardly between the mutually inclined inner sides of the wall members 3, 3a.

Inwardly of the wall members 3, 3a, there is provided a pair of similar annular partitions 5, 5a which are respectively secured to the inner sides of the end walls 1, 1a and define between themselves a second annular gap or passage 6 which latter communicates with the chamber 7 formed by the parts 3, 3a and 5, 5a between the end walls 1, 1a. The annular partitions 5, 5a and the drive shaft 2 define between the end walls an annular compartment 8 which communicates with the chamber 7 through the annular passage 6. The chamber 7 will be called washing chamber and the compartment 8 will be called solids-collecting compartment.

The drive shaft 2 is rotatable in bearings 9, 10 disposed at the outer sides of the respective end walls 1a, 1, and is rotatable by a drive means including a pulley 11 forming part of the hub 1a and belting 11a, the latter driven by a suitable electric motor or the like, not shown. Of course, the pulley-and-belt drive 11, 11a may be replaced by other types of drive means, e.g. a gear train or the like.

The flow of material through the gap 4 and through the passage 6 is respectively controlled by elastic sealing rings 12, 13 which actually constitute a pair of inflatable and deflatable annular sealing gaskets so as to selectively permit the evacuation of material from the washing chamber 7 radially outwardly through the gap 4 and to selectively permit the evacuation of solid component or fraction from the solids-collecting compartment 8 into the washing chamber.

The suspension which must be separated into a solid and a liquid component or fraction is introduced at an elevated pressure through a stationary supply pipe 14 in the direction of the arrow 14a, and thereupon flows through the hollow drive shaft 2 in a direction to the left, as viewed in FIG. 1, to enter the compartment 8 through a plurality of radial inlet ports 15 formed in the wall of the drive shaft between the right-hand end wall 1a and a closing wall 18 which latter forms a transverse seal in the interior of the drive shaft at a point adjacent to and located inwardly of the left-hand end Wall 1. On its way from the inlet ports 15 into the outer zone of the compartment 8, the material flows between axially parallel separator vanes 16 (FIG. 2) or between radial separator disks 17 (see FIGS. la and 2a) which guide the solid component in a direction radially outwardly toward the ring 13 while the liquid component passes through radial discharge ports 19 formed in the Shaft 2 to the left of the closing wall 18, and back into the interior of the hollow drive shaft 2 to be withdrawn through a stationary discharge pipe 20 in the direction indicated by the arrow 20a.

A pressure conduit 21 which extends into the discharge pipe 20 and coaxially into the left-hand portion of the drive shaft 2 delivers a pressurized hydraulic fluid (e.g. water) into a plurality of radially arranged distributor channels 22 which pass through the wall of the drive shaft 2 and through the hub 1' of the left-hand end Wall 1, and which communicate with an annular inner distributor channel 23 formed about the hub 1'. The right-hand end of the conduit 21 is spaced from the closing wall 18.

Referrin to FIG. 3, it will be seen that the annular distributor channel 23 communicates with a pair of radial channels 24, 31 which respectively communicate with annular outer distributor channels 25, 32. The channels 25, 32 respectively communicate with a plurality of comparatively strong, uniformly distributed axially parallel connecting tubes 26, 26a which extend between the end Walls 1, 1a. The tubes 26 extend through the inner ring 13, and the tubes 26a extend through the outer ring 12. FIG. 4 shows a tube 26 which is assumed to pass through the ring 13 and which comprises externally threaded portions meshing with a pair of nuts 27, the latter pressing a pair of annular sealing washers 61) against the opposite outer sides of the ring 13 so as to make sure that the pressure fluid admitted to the interior of the inflatable and deflatable ring 13 from the pressure conduit 21 and through the connecting tubes 26 will not escape into the chamber '7 or into the compartment 8. The internal space of the elastic ring 13 receives an annular disk-shaped element 28 which is formed with axially parallel bores 29 and with radial bores 30, the latter communicating with the respective bores 29 and with the interior of the respective connecting tubes 26 so that fluid delivered through the tubes 26 may flow through the radial bores 30 and through the axially parallel bores 29 into the interior of the ring 13 to inflate the same and to cause this ring to sealingly engage the adjacent portions of partitioning annuli 5, 5a in order to prevent the flow of material through the passage 6. When the ring 13 in inflated, it assumes the position 13' as shown in the right-hand half of FIG. 4. On the other hand, when the ring 13 is deflated, it assumes the position 13" shown in the lefthand half of FIG. 4 so as to permit the flow of material from the compartment 8 to the washing chamber 7. The Washers 60 press the radially outwardly extending flanks of the ring 13 against the respective outer sides of the element 28.

Referring to FIG. 5, there is shown the outermost portion of the ring 13 which is traversed by a plurality of preferably uniformly spaced axially parallel bolts 61 (only one shown) which, by means of nuts 61a, sealingly press the washers 60 against the flanks of the ring 13 and thereby compel this ring to sealingly engage the outer sides of the outermost portion of the element 28. In other words, the internal space of the ring 13 can communicate with the interior of the connecting tubes 26 but is otherwise completely sealed from the chamber 7 and from the compartment 8. The mounting of the ring 12 and the manner of its communication with the connecting tubes 25a are analagous and, therefore, are not shown in the drawings.

The pressure conduit 21 further serves as a means for conveying hydraulic washing fluid to the chamber 7.

5. To that end, the annular channel 23 communicates with two additional radial channels 33, see FIG. 3, which lead to an annular channel 34 provided at the outer side of the end wall 1. The channel 34 communicates with a plurality of preferably uniformly spaced axially parallel connecting tubes 35 which extend between the end walls 1, 1a. As shown in FIG. 1a, each connecting tube 35 is formed with radial bores 35a through which the fluid conveyed through the conduit 21 may enter the washing chamber 7.

The means for controlling the admission of fluid to the annular channels 25, 32 and 34 comprises electromagnetic or solenoid valves which are shown in FIGS. 9-10b and 11-11a. FIGS. 9, 9a, 10, a and 10b show an electromagnetic valve 36 which is mounted at the outer side of the end wall 1 and which is assumed to control the flow of pressure liquid from the radial channel 24 to the annular distributor channel 25. The valve 36 is connected with a non-illustrated source of electrical energy through a collector 36A which is provided about the hub 1' of the left-hand end wall 1 (see FIG. 1), and comprises a valve member 38 which is premanently biased by a resilient element in the form of a helical spring 36a so as to move in a direction to the left and to assume the position of FIG. 9 in which it permits the flow of pressure fluid from the radial channel 24 through the valve casing 37 and into the annular channel 25. When the valve 36 is energized, the member 38 is moved to the right to assume the position of FIG. 9a in which the pressure fluid cannot flow from the radial channel 24 through the valve casing 37 and into the annular channel 25. As shown in FIGS. 9 and 9a, the valve member 38 comprises two spaced pistons 33a, 38b and a connecting rod 38c. In the position of FIG. 9a, the piston 38a seals the intake 37a in the casing 37, while the piston 38b permits the outlet 37b of the valve housing 37 to communicate with a duct 37c communicating with the space surrounding the separator housing so that the fluid previously admitted to the internal space of the ring 13 is automatically evacuated from the separator housing and the ring 13 may assume the deflated position 13" (see FIG. 4) in which it permits the discharge of solid component from the compartment 8 into the washing chamber 7 by exposing the passage 6 between the annuli 5, 5a. In the position of FIG. 9, the piston 38b prevents the escape of pressure fluid from the valve housing 37 by sealing the duct 370 but permits the flow of fluid from the intake 37a to the outlet 37b so that the fluid conveyed through the radial channel 24 may flow into the annular channel 25 and through the tubes 26 into the internal space of the ring 13.

The modified solenoid valve 136 of FIGS. 11 and 11a comprises a valve casing 137 which is formed with a longer duct 137s so that, even if the valve 136 is energized, the rod 1380 of the valve member 138 cannot move the piston 138b to a position in which the pressure fluid could be discharged through the duct 1370. Otherwise, the construction of the valve 136 is identical with that of the valve 36, i.e. the piston 138a may selectively seal or unseal the intake 137a from the outlet 137b, depending upon whether the valve member 138 is free to follow the bias of the valve spring (FIG. 11) or is compelled to move to the position of FIG. 11a when the valve 136 is energized. The construction of the valves controlling the flow of pressure fluid from the respective radial channels 31, 33 to the annular channels 32, 34 may be the same as shown in FIGS. 9, 9a or 11, 11a.

In FIG. 3, it is assumed that the valves which control the flow of fluid to the channels 25, 32 are constructed in a manner as shown in FIGS. 9 and 9a. The valve 136 of FIGS. 11, 11a is of particular advantage for controlling the admission of pressure fluid to the washing chamber 7, i.e. the flow of pressure fluid from the radial channels 33 to the annular channel 34 is preferably controlled by the valves 136.

In centrifugal separators of the type to which the preent invention pertains, certain problems are encountered in connection with the admission of the suspension from the supply pipe 14 into the hollow drive shaft 2 and in connection with the evacuation of clarified liquid component from the compartment 8. Thus, it is desirable to prevent relative movements between the shaft 2 and the suspension contained therein in the zone Where the suspension passes through the inlet ports 15 and into the compartment 8. In other words, it is desirable to angularly accelerate the suspension between the discharge end of the supply pipe 14 and the ports 15 to such an extent that the suspension will follow rotational movements of the shaft 2 at the latters speed when it reaches the ports 15. FIGS. 7, 7a and 7b illustrate an arrangement which continuously accelerates the suspension in the interior of the drive shaft 2. This arrangement comprises a stationary hollow spindle 39 (see also FIG. 1) which extends into the supply pipe 14 and to the left concentrically into the interior of the drive shaft 2 toward but short of the closing wall 18. The left-hand end portion of the spindle 39 carries substantially radial blades 40 whose left hand end portions are curved in a manner shown in FIG. 71; so as to cause the suspension admitted through the supply pipe 14 to spin in the angular direction 41 in which the shaft 2 is driven. The suspension is admitted at a certain pressure and, therefore, the blades 41 act as turbine blades to bring about angular movement of the suspension in the drive shaft 2. The suspension advancing through the sector-shaped spaces between the adjacent blades 40 flows toward a second group of blades 42 (see FIGS. 7a and 7b) mounted on a short shaft 43 concentrically received in the drive shaft 2 and connected for rotation with the closing wall 18. The shaft 43 extends toward but short of the left-hand end of the spindle 39. The rotary blades 42 are bent in such a way that the suspension discharged from the sector shaped spaces between the fixed blades 40 enters substantially tangentially into the sector shaped spaces between the blades 42 and is then automatically accelerated to the rotational speed of the shaft 2 before it can reach the inlet ports 15. As explained hereinabove, the suspension entering through the radial inlet ports 15 comes into contact with the vanes 16 or with the disks 17 on its way radially outwardly toward the outer zone of the compartment 8, depending upon whether the separator is constructed in a manner shown in FIGS. 1, 2 or 1a, 2a.

Another problem which must be overcome in assembling the centrifugal separator of FIG. 1 is that of providing leakproof couplings between the stationary pipes 14, 20 and the respective ends of the rotary drive shaft 2. One such sealing coupling 45 is shown in FIG. 8. This coupling is assumed to be provided between the drive shaft 2 and the supply pipe 14. The coupling 45 between the shaft 2 and the discharge pipe 241 is of identical construction.

Referring now in greater detail to FIG. 8, the coupling 45 comprises a radially outwardly extending annular flange 44 which is fixed to the discharge end of the supply pipe 14, and a flange-like radially outwardly extending housing element 45a which is fixed to the adjacent end of the drive shaft 2 and which carries an annular portion or member 46 that overlaps but is spaced from the flange 44. As shown in FIG. 8, a clearance 47 is provided between the flange 44 on the one hand and the parts 45a, 46 on the other hand so that the shaft 2 and the parts connected therewith are not in actual contact with the pipe 14 or with the flange 44. The clearance 47 communicates with an annular space provided in the interior of the element 45a. This annular space receives a supply of mercury M which, when the shaft 2 is not driven, accumulates in the lower part of the element 45a and also fills the lower part of the clearance 47. When the pulley-and-belt drive 11, 11a rotates the shaft 2, the mercury is thrown by centrifugal force against the outer wall of the element 45a and thereby fills the clearance 47 to the extent shown in the upper part of FIG. 8 so as to form a liquid-tight annular seal between the internal space of the element 45a and the surrounding atmosphere and to thereby prevent escape of the suspension which advances from the pipe 14 into the interior of the drive shaft 2. Depending on the pressure at which the suspension is admitted into the shaft 2, and depending on the rpm. of the shaft 2, the layer of mercury in the clearance 47 may assume different positions as indicated by the reference numerals 43 and 49. The width of the clearance 47 may be selected in dependency on the operating conditions. It will be noted that the arrangement of FIG. 8 constitutes an advantageous substitute for a stufiing box because it permits the shaft 2 to rotate with respect to the pipe 14 without any or with negligible friction such as is produced by the mercury layer in the clearance 47. When the housing 1, 1a. 3, 3a of the centrifugal separator is arrested, the mercury descends into the lower part of the element 45a and the interior of the shaft 2 is free to communicate with the surrounding atmosphere. A certain quantity of mercury located in that part of the clearance 47 which extends between the right-hand side of the flange 44 and the adjacent portion of the annular member 46 descends into a collecing groove 5t) of the flange 44 and is returned into the internal space of the element 45a as soon as the shaft 2 is brought to a standstill.

I will now describe certain other features which contribute to improved separating action of my apparatus. Referring to FIGS. 1, 2 and la, 2a, the vanes 16 or the disks 17 are bounded by a pair of plate-like weirs 51 which are secured to the shaft 2 and which define with the end walls 1, 1a a pair of spaced collecting chambers 52 which collect the clarified liquid component of the suspension and which communicate with the discharge ports 19. As shown in the drawings, the collecting chambers 52 communicate with each other through a plurality of preferably uniformly spaced tubular conductors 53 which extend through the weirs 51 and are parallel with the axis of the drive shaft 2. These conductors 53 also serve as a means for maintaining the vanes 16 or the disks 17 in assembled position as shown in FIG. 1 for the vanes 16. To that end, the ends of the conductors 53 are formed with hollow heads which prevent radial and/ or axial displacements of the Weirs 51.

Adjacent to the outer ends of the vanes 16 or of the disks 17, the solids-collecting compartment 8 is divided into a plurality of smaller compartments by axially parallel radially outwardly extending bafiles 54 which extend between the mutually inclined inner sides of the annuli 5, 5a. Similar baflles 55 are provided between the inner sides of the outer annuli 3, 3a so as to subdivide the washing chamber 8 into a plurality of smaller chambers. In order to insure better distribution of clarified liquid component to the collecting chambers 52, the apparatus comprises a disk-shaped separating wall 16a which extends midway between the weirs 51 and radially outwardly toward the ring 13. As shown in FIG. 1, the compartment 8 is divided into two halves by an annular baffie 8a which surrounds the separating wall 16a at the inner side of the ring 13 and is connected with the radial baffies 54 so that each small chamber defined by the adjacent baffies 54 is subdivided by the wall 8a into a portion adjacent to the end wall 1 and into a portion adjacent to the end wall In. A similar bathe 7a which is preferably coplanar with the bafile 3a and with the separating wall 16a divides the washing chamber 7 into two halves. It will be noted that the separating wall 16a and the baffles 7a, 8a are located in a plane which is perpendicular to the axis of the drive shaft 2 and are located substantially midway between the end walls 1, 1a. The outer ends of the vanes 16 or of at least some disks preferably extend beyond the outer ends of the weirs 51.

FIG. 1 shows that additional vanes 16' may be provided in each of the collecting chambers 52. Analogously, additional disks 17 may be provided in the chambers 5.2 if the separator assumes the form shown in FIG. 2a. The disks 17 are located in planes perpendicular to the axis of the shaft 2.

Referring to FIG. 6, there is shown a leakproof coupling 56 which is provided between the pressure conduit 21 and the rotary part of the separator, i.e. the radial channels 22. This coupling comprises a sleeve 56a which is screwed onto the discharge end of the conduit 21 and which receives an axially slidable nozzle 57 formed with a tapering discharge orifice 58. This nozzle acts as a plunger and bears with its front end face against the adjacent end face of a nipple 59 secured to and rotating with the closing wall 19. The channels 22 extend radially outwardly from the nipple 59 and the latter is formed with an orifice 5911 which communicates with the orifice 58. When the washing fluid is admitted through the conduit 21, it presses the axially movable nozzle 57 against the nipple 59 and thus provides an automatic sealing connection between the parts 57, 59. It will be readily understood that the tapering orifice 53 restricts the flow of fluid and thereby causes the fluid to maintain the nozzle 57 in abutment with the nipple 59 whereby the abutting end faces of the parts 57, 59 automatically prevent the escape of any or nearly any fluid therebetween. The nozzle 57 is freely rotatable in the sleeve 56 so that the friction is reduced to a minimum. Leakage of some fluid between the nozzle 57 and the nipple 59 or between the nozzle 57 and the sleeve 56 is not detrimental since the fluid, usually pure water, is merely admixed to the clarified liquid component passing from the discharge ports 19 to the discharge pipe 20.

The separator of my invention operates as follows:

The suspension is normally admitted to the supply pipe 14 at a pressure of 6-15 in. water column. Such pressure is sufiicient to cause a spinning of suspension as the latter passes through the sectors between the curved blades 40 of the stationary spindle 39. In addition, such pressure enables the suspension to overcome the resistance to flow in the pipe 14, in the shaft 2 and in the inlet ports 15. If the suspension is hot, i.e. if its temperature is say C., the pressure must be selected in such a way as to prevent the formation of vapors.

At the outset of a working cycle, the rings 12, 13 are filled with pressure fluid, i.e. the solenoid valves 36 are deencrgized so that the valve springs 36a permit the hydraulic pressure fluid to pass to the connecting tubes 26 and 26a whereby the rings 12, 13 respectively seal the gap 4 and the passage 6. The washing chamber 7 is filled with fluid admitted through the bores 35a of the connecting tubes 35 because the solenoid valves 136 are deenergized. The fluid in the rings 12, 13 is subjected to pressure by a pressure source, e.g. a pump 21a or the like (see FIG. 1), whose pressure side is connected with the conduit 21 and whose suction side is connected with a suitable source of hydraulic fluid, e.g. a water tank 21b shown in FIG. 1. The pressure of fluid in the washing chamber 7 depends on the rpm. of the separator, on the specific weight of the suspension, and on the specific weight of the solid component in the suspension. This fiuid pressure must be higher than the pressure produced in the compartment 8 by centrifugal force to insure that the rings 12, 13 remain in sealing position. The suspension streams through the ports 15 into the spaces between the vanes 16 or the disks 17, and is separated into a liquid component which flows into the chambers 52 and connectors 53 to be discharged through the ports 19 into the discharge pipe 20, and into a solid component which accumulates in the outer zone of the compartment 8.

Once the compartment 8 is filled with solid material, the solenoid valve 36 which controls the flow of pressure fluid to the ring 13 is energized to seal the internal space of the ring 13 from the conduit 21 and to permit the fluid to escape from the ring 13 through the duct 37c whereby the ring assumes the deflated position 13" as 9 shown in FIG. 4. The width of passage 6 at both sides of the ring 13 is a multiple of the maximum dimensions of largest solid particles contained in the suspension. For example, the width of the passage 6 between the partitions 5, a and the ring 13 may be in the range of 1-2 mm. if the solid component is in the form of fine mud. Simultaneously with deflation of the ring 13, the valves 136 are energized to shut off the flow of fluid to the washing chamber 7 so that a pressure equalization takes place in the chamber 7 and compartment 8 whereby the solid component automatically penetrates through the passage 6 and into the chamber 7 because its specific weight is higher than the specific weight of the hydraulic fluid. The fluid flow countercurrently from the chamber 7 through the passage 6 and into the compartment 8. Such countercurrent flow of fluid and solid component through the passage 6 insures that each solid particle comes at least into short-lasting contact with the fluid and that any soluble matter entrained with the solid particles is dissolved before the centrifuging operation is completed. Furthermore, any liquid matter entrained with the solid component into the outer zone of the compartment 8 is caused to be separated from the particles passing through the passage 6 so that a highly concentrated solid component accumulates in the washing chamber 7. The fluid flowing from the chamber 7 into the compartment 3 is enriched with dissolved material and with the liquid phase and flows inwardly toward the chambers 52 and ports 19 to be evacuated through the discharge pipe 20. In order to make sure that the liquid component or phase of the suspension cannot penetrate into the chamber 7, it is preferred to shut ofi' the delivery of fluid to the chamber 7 shortly after the passage 6 is opened by deflation of the ring 13. For example, the length of the interval between the opening of the passage 6 and the shutting ofi of fluid supply to the washing chamber 7 may be in the range of 1-2 seconds.

The washing operation in the chamber 7 is completed within a very short period of time, i.e. within seconds. As soon as this washing operation is completed, the ring 13 is inflated to seal the passage 6 simultaneously with deflation of the ring 12 to permit evacuation of the washed solid component from the washing chamber. Under the influence of centrifugal force, the solid component passes through the gap 4 into an annular mantle 62 which surrounds the wall members 3, 3a. This mantle is provided with one or more slits 62a through which the solid componen is ejected into a stationary collecting trough 63 extending about the mantle 62. It is preferred to deenergize the valves 136 when the gap 4 is open so that pressure fluid (water) may penetrate into the chamber 7 while the solid component is being evacuated therefrom. This insures that the solid component is evacuated in diluted state, and the pressure fluid also prevents entry of atmospheric air into the chamber 7.

The sequence of operating steps may be controlled in a very simple manner. For example, a manometer may be connected with the separator housing to determine the pressure prevailing in the washing chamber 7. This manometer determines the difference in pressures prevailing in the chamber 7 when the latter is filled with pressure fluid or with the solid component, and may serve as a means for actuating the solenoid valves 36 and 136.

It is advisable to construct the separator housing in such a way that the volume of the solids-collecting compartment 3 is larger than the volume of the washing chamber 7. Such construction insures that the passage 6 is at least partly covered by the solid component during and after completion of the washing operation.

Though the separator of my invention normally operates continuously, the solid component may be evacuated at certain intervals. A complete Working cycle may be terminated within about 20 seconds.

The improved centrifugal separator is of particular advantage for use in the production of sugar. Thus, the

extracted juice introduced into the apparatus is separated into a liquid portion or component and into a solid portion, and the latter is automatically washed with water while passing from the compartment 8 into the chamber 7. Heretofore, the solid component was washed in a step following the centrifugal separation and was thereupon separated from the washing fluid by suitable filters or the like. The chamber 7 and the compartment 8 are sealed from the atmosphere as soon as the sealing ring 12 is inflated by admission of pressurized hydraulic washing fluid to the tubes 26a and as soon as the shaft 2 begins to rotate since the layer of mercury in the clearances 47 then automatically seals the couplings 45 and 45'. The admission of juice to the compartment 8 and the withdrawal of liquid component from this compartment need not be interrupted even though the solid component is withdrawn only periodically from the washing chamber 7.

The utilization of my improved separator in the production of sugar brings about certain other important advantages. Heretofore, the initial evaporating or separating step, the main evaporating or separating step, and the first saturation were mainly intended to bring the colloidal matter contained in the extracted juice into a state suitable for filtration, i.e. to provide the colloidal matter with a coat of calcium carbonate so that it may be readily filtered from the juice. The addition of calcium hydroxide and carbon dioxide can now be reduced to a minimum because these substances are added merely with a view to purify the juice but not to facilitate removal of colloidal matter therefrom. Such separation can be carried out very satisfactorily in my improved separator. Consequently, since the colloidal matter may be separated immediately after the first saturation, the undesirable effects of the alkaline colloidal matter on the liquid component, particularly the color-changing effect, are reduced to a minimum. Also, since the addition of calcium hydroxide and of carbon dioxide is reduced to a minimum, the solid component may be utilized, upon minimal additional processing, as animal fodder or the like.

Of course, the separator of my invention may be utilized with equal advantage in many other branches of industry, for example, in breweries and in other plants where the suspension is separated at elevated temperatures or where the suspension contains a gaseous component.

The provision of vanes 16 or disks 17 in the compartment 8 insures that the suspension is caused to flow in a number of streams and at a comparatively low rate of speed radially outwardly toward the passage 6, i.e. both components of the suspension advance initially in the same direction though the solid particles advance at a higher speed. However, the difference in speed of the solid and liquid component is not suflicient to cause turbulence in the compartment 8. The separation into a liquid and into a solid component is terminated at the outermost radial ends of the vanes 16 or disks 17. As the liquid component then flows through the chambers 52 toward the tubes 53 or directly toward the discharge ports 19, the auxiliary vanes 16' separate any remaining solid particulate matter therefrom. Such separation of remaining solid particles is possible because the rate of flow in the chambers 53 is comparatively slow.

Without further analysis, the foregoing will so fully eveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic and specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is:

l. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, comprising a rotary housing having an annular solids-collecting compartment, an annular washing chamber surrounding said compartment, and passage means communicatively connecting said compartment with said chamber; sealing means for selectively closing and opening said passage means so that the solid component separated from a suspension introduced into said compartment at elevated pressure is free to pass into said chamber when the passage means is open and the housing rotates; and means for admitting a hydraulic washing fluid into said chamber, the area of said passage means in open position thereof being such that the solid component is rapidly diluted by the Washing fluid and penetrates into said chamber so as to expel corresponding quantities of washing fluid from said chamber into said compartment when said passage means is open whereby the fluid washes the solid component while passing from said chamber and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component.

2. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, comprising a rotary housing having an annular solids-collecting compartment, an annular washing chamber surrounding said compartment, annular passage means communicatively connecting said compartment with said chamber, and annular gap means for permitting evacuation of material from said washing chamber; first annular sealing means for selectively closing and opening said passage means so that the solid component separated from a suspension introduced into said compartment at elevated pressure is free to pass into said chamber when said passage means is open and the housing rotates; second annular sealing means for selectively closing and opening said gap means so that the solid component accumulating in said washing chamber may be evacuated therefrom when said gap means is open and the housing rotates; and means for admitting a hydraulic washing fluid into said chamber, the area of said passage means in open position thereof being such that the solid component is rapidly diluted by the washing fluid and penetrates into said chamber so as to expel corresponding quantities of fluid from said chamber into said compartment when said passage means is open whereby the fluid Washes the solid component while passing from said chamber and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component.

3. A centrifugal apparatus for separating a suspension r into a solid and a liquid component, particularly for separating extracted sugar juice, comprising a rotary drum having an annular solids-collecting compartment, an annular washing chamber surrounding said compartment, an annular passage communicatively connecting said compartment with said chamber, and an annular gap for permitting evacuation of material radially outwardly from said chamber; first inflatable and deflatable annular sealing means for selectively closing and opening said passage so that the solid component separated from a suspension introduced into said compartment at elevated pressure is free to pass into said chamber when said passage is open in response to deflation of said sealing means and when the drum rotates; second inflatable and deflatable annular sealing means for selectively closing and opening said gap so that the solid component accumulating in said chamber may be evacuated therefrom when said gap is open in response to deflation of said second sealing means and when the drum rotates; a source of hydraulic pressure fluid; means for selectively admitting fluid from said source into said chamber, the area of said passage in open position thereof being such that the solid component is rapidly diluted by the Washing fluid and penetrates into said chamber so as to expel corresponding quantities of fiuid from said chamber into said compartment when said passage is open whereby the fluid washes the solid component while passing from said chamber and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component; means for connecting said source with said first and second sealing means so that the fluid may inflate said sealing means to respectively close said passage and said gap; and valve means for regulating the flow of fluid to and from said sealing means so as to permit deflation of the sealing means and consequent opening of said passage and said gap.

4. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, comprising a rotary housing having an annular solids-collecting compartment, an annular washing chamber surrounding and having a volume smaller than the volume of said compartment, and passage means communicatively connecting said compartment with said chamber; sealing means for selectively closing and opening said passage means so that the solid component separated from a suspension introduced into said compartment at elevated pressure is free to pass into said chamber when the passage means is open and the housing rotates; and means for admitting a hydraulic washing fluid into said chamber, the area of said passage means in open position thereof being such that the solid component is rapidly diluted by the washing fluid and penetrates into said chamber so as to expel corresponding quantities of fluid from said chamber and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component into said compartment when said passage means is open whereby the fluid washes the solid component while passing from said chamber.

5. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, said apparatus comprising a hollow drive shaft including an internal closing wall; a drum concentric-ally mounted on and rotatable with said drive shaft, said drum comprising a pair of spaced end walls, annular partitioning means disposed intermediate said end walls and defining an annular passage, annular Wall means disposed between said end walls and spacedly surrounding said partitioning means, said annular Wall means defining an annular gap for the evacuation of material from said drum, said partitioning means and said shift defining between said end walls an annular solidscollecting compartment, said shaft having inlet port means located at one side of said closing wall for permitting a suspension introduced into said shaft at elevated pressure to How into said compartment, and discharge port means located at the other side of said closing wall and communicating with said compartment for permitting evacuation of the liquid component which is separated from the suspension in said compartment, said annular wall means and said partitioning means defining between said end walls an annular washing chamber surrounding said compartment and communicating therewith through said passage; a source of hydraulic pressure fluid; means for admitting the fluid from said source into said chamber; first inflatable and deflatable annular sealing means for selectively closing and opening said passage, the area of said passage in open position thereof being such that the solid component separated from the suspension in said compartment in response to rotation of said drum is free to pass through the open passage and is rapidly diluted by the fluid to penetrate into said chamber and to expel corresponding quantities of fluid into said compartment whereby the fluid washes the solid component while passing into said compartment and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component; second inflatable and deflatable annular sealing means for selectively closing and opening said gap so that the solid component accumulated in said chamber may be evacuated from said drum by centrifugal force when the gap is open and the shaft rotates; means for connecting said source with said first and second sealing means so that the fluid may inflate the same; and valve means for regulating the flow of fluid to and from said sealing means so that the sealing means may be deflated to open said passage and said gap.

6. An apparatus as set forth in claim 5, further comprising a plurality of separator vanes disposed in said compartment and located in radial planes substantially parallel with the axis of said drive shaft.

7. An apparatus as set forth in claim 6, further comprising separator wall means in said compartment, said separator wall means being disposed substantially midway between said end walls and being located in a plane substantially perpendicular to the axis of said drive shaft.

8. An apparatus as set forth in claim 5, further comprising a plurality of separator disks disposed in said compartment and located in planes perpendicular to the axis of said drive shaft.

9. An apparatus as set forth in claim 5, further comprising substantially plate-like weir means disposed in said compartment and defining with said end walls collecting chambers for the liquid component, said collecting chambers communicating with said discharge port means, and a plurality of separator elements disposed between said weir means.

10. An apparatus as set forth in claim 9, further comprising additional separator elements in said collecting chambers.

11. An apparatus as set forth in claim 9, wherein said separator elements are radial vanes.

12. An apparatus as set forth in claim 11, wherein said vanes extend radially outwardly beyond said weir means.

13. An apparatus as set forth in claim 9, further comprising tubular connector means extending between said weir means for communicatively connecting said collecting chambers with each other, said connector means substantially parallel with the axis of said drive shaft.

14. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for sepanating extracted sugar juice, said apparatus comprising a hollow drive shaft including an internal closing wall; a drum concentrically mounted on and rotatable with said drive shaft, said drum comprising a pair of spaced end walls, a pair of annular partitions disposed intermediate and each rigid with one of said end walls, said partitions tapering toward each other in a direction radially out- Wardiy from said drive shaft and defining an annular passage therebetween, a pair of annular wall members disposed between and each rigid with one of said end walls, said wall members concentrically surrounding said partitions and tapering toward each other in a direction radially outwardly from said drive shaft so as to define an annular gap through which the solid component may be evacuated from said drum, said partitions and said shaft defining between said end walls an annular solidscollecting compartment, said shaft having inlet port means located at one side of said closing wall for permitting a suspension introduced into said shaft at elevated pressure to flow into said compartment, and discharge port means located at the other side of said closing wall and communicating with said compartment for permitting evacuation of the liquid component which is separated from the suspension in said compartment, said wall members and said partitions defining between said end walls an annular washing chamber surrounding said compartment and communicating therewith through said passage; a source of hydraulic pressure fluid; means for admitting the fluid from said source into said chamber; first inflatable and deflata'ble annular sealing means for selectively closing and opening said passage, the area of said passage in open position thereof *being such that the solid component separated from the suspension in said compartment in response to rotation of said drum is free to pass through the open passage and is rapidly diluted by the fluid to penetrate into said chamber and to expel corresponding quantities of fluid into said compartment whereby the fluid washes the solid component while passing into said compartment and entrains into said comp-artment at least some of the liquid component which might have been entrapped in the undiluted solidcomponent; second inflatable and deflatable annular sealing means for selectively closing and opening said gap so that the solid component accumulated in said chamber may be evacuated from said drum when the gap is open and the shaft rotates; means for connecting said source with said first and second sealing means so that the fluid may inflate the same; and valve means for regulating the flow of fluid to and from said sealing means so that the sealing means may be deflated to open said passage and said gap.

15. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, said apparatus comprising a hollow drive shaft including an internal closing wall; a drum concentrically mounted on and rotatable with said drive shaft, said drum comprising a pair of spaced end walls, annular partitioning means disposed intermediate said end walls and defining an annular passage, annular wall means disposed between said end walls and spacedly surrounding said partitioning means, said annular wall means defining an annular gap for the evacuation of material from said drum, said partitioning means and said shaft defining between said end walls an annular solids-collecting compartment, said shaft having inlet port means located at one side of said closing wall for permitting a suspension introduced into said shaft at elevated pressure to flow into said compartment, and discharge port means located at the other side of said closing wall and communicating with said compartment for permitting evacuation of the liquid component which is separated from the suspension in said compartment, said annular wall means and said partitioning means defining between said end walls an annular washing chamber surrounding said compartment and communicating therewith throu-gh said passage; a source of hydraulic pressure fluid; means for admitting the fluid from said source into said chamber, said fluid admitting means comprising a fixed pressure conduit extending into said drive shaft, rotary channel means provided on one of said end walls for conveying the fluid to said chamber, and coupling means for conveying the fluid from said conduit to said channel means; first inflatable and deflatable hollow annular sealing means for selectively closing and opening said passage, the area of said passage in open position thereof being such that the solid component separated from the suspension in said compartment in response to rotation of said drum is free to pass through the open passage and is rapidly diluted by the fluid to penetrate into said chamber and to expel corresponding quantities of fluid into said compartment whereby the fluid washes the solid component while passing into said compartment and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component; second inflatable and deflatable hollow annular sealing means for selectively closing and opening said gap so that the solid component accumulated in said chamber may be evacuated from said drum when the gap is open and the shaft rotates; means for connecting said source with said first and second sealing means so that the fluid may inflate the same, said connecting means comprising tube means communicating with said channel means and with said sealing means; and valve means provided in said channel means for regulating the flow of fluid to and from said sealing means so that the sealing means may be deflated to open said passage and said gap.

16. An apparatus as set forth in claim 15, wherein said channel means comprises a first annular channel, radial channel means communicatin with said annular channel and with said coupling means, a second annular channel communicating with said first sealin means, a third annular channel communicating with said second sealing means, a fourth annular channel communicating with said chamber, and radial channel means respectively connecting said first annular channel with said second, third and fourth annular channels.

17. An apparatus as set forth in claim 15, wherein said coupling means comprises a hollow nipple connected to and rotatable with said closing wall and communicating with said channel means, a sleeve provided on said pressure conduit adjacent to and aligned with said nipple, and a nozzle reciprocably received in said sleeve and movable into and from abutment with said nipple, said nozzle having orifice means tapering in a direction toward said nipple whereby the fluid passing through said orifice means urges the nozzle into abutment with said nipple and the fluid flows from said nozzle and through said nipple into said channel means.

18. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, said apparatus comprising a hollow drive shaft including an internal closing wall; a drum concentrically mounted on and rotatable with said drive shaft, said drum comprising a pair of spaced end walls, annular partitioning means disposed intermediate said end walls and defining an annular passage, annular wall means disposed between said end walls and spacedly surrounding said partitioning means, said annular wall means defining an annular gap for the evacuation of material from said drum, said partitioning means and said shaft defining between said end walls an annular solids-collecting compartment, said shaft having inlet port means located at one side of said closing wall for permitting a suspension introduced into said shaft at elevated pressure to flow into said compartment, and discharge port means located at the other side of said closing wall and communicating with said compartment for permitting evacuation of the liquid component which is separated from the suspension in said compartment, said annular wall means and said partitioning means defining between said end walls an annular washing chamber surrounding said compartment and communicating therewith through said passage; supply conduit means for introducing the suspension into said drive shaft; means provided in said drive shaft at said one side of the closing wall for accelerating the suspension substantially to the rotational speed of said drive shaft before the suspension reaches said inlet port means; a source of hydraulic pressure fluid; means for admitting the fluid from said source into said chamber; first inflatable and deflatable annular sealing means for selectively closing and opening said passage, the area of said passage in open position thereof being such that the solid component separated from the suspension in said compartment in response to rotation of said drum is free to pass through the open passage and into said chamber and to expel corresponding quantities of fluid into said compartment whereby the fluid Washes the solid component while passing into said compartment and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component; second inflatable and deflatable annular sealing means for selectively closing and opening said gap so that the solid component accumulated in said chamber may be evacuated from said drum when the the gap is open and the shaft rotates; means for connecting said source with said first and second sealing means so that the fluid may inflate the same; and valve means for regulating the flow of fluid to and from said sealing means so that the sealing means may be deflated to open said passage and said gap.

19. An apparatus as set forth in claim 18, wherein said accelerating means comprises fixed blade means extending into said drive shaft and spaced from said closing wall, said blade means having curved portions for imparting a spinning motion to the suspension, and rotary blade means fixed to and rotatable with said closing wall, said rotary blade means located between said fixed blade means and said closing wall for imparting additional spinning motion to the suspension before the suspension reaches said inlet port means.

20. A centrifugal apparatus for separating a suspension into a solid and a liquid component, particularly for separating extracted sugar juice, said apparatus comprising a hollow drive shaft including an internal closing wall; supply conduit means for introducing the suspension into said drive shaft; leakproof coupling means between said drive shaft and said conduit means; a drum concentrically mounted on and rotatable with said drive shaft, said drum comprising a pair of spaced end walls, annular partitioning means disposed intermediate said end walls and defining an annular passage, annular wall means disposed between said end walls and spacedly surrounding said partitioning means, said annular wall means defining an annular gap for the evacuation of material from said drum, said partitioning means and said shaft defining between said end walls an annular solids-collecting compartment, said shaft having inlet port means located at one side of said closing wall for permitting a suspension introduced into said shaft at elevated pressure to flow into said compartment, and discharge port means located at the other side of said closing wall and communicating with said compartment for permitting evacuation of the liquid component which is separated from the suspension in said compartment, said annular wall means and said partitioning means defining between said end walls an annular washing chamber surrounding said compartment and communicating therewith through said passage; a source of hydraulic pressure fluid; means for admitting the fluid from said source into said chamber; first inflatable and deflatablc annular sealing means for selectively closing and opening said passage, the area of said passage in open position thereof being such that the solid component separated from the suspension in said compartment in response to rotation of said drum is free to pass through the open passage and is rapidly diluted by the fluid to penetrate into said chamber and to expel corresponding quantities of fluid into said compartment whereby the fluid washes the solid component while passing into said compartment and entrains into said compartment at least some of the liquid component which might have been entrapped in the undiluted solid component; second inflatable and dcflatable annular sealing means for selectively closing and opening said gap so that the solid component accumulated in said chamber may be evacuated from said drum when the gap is open and the shaft rotates; means for connecting said source with said first and second sealing means so that the fluid may inflate the same; and valve means for regulating the flow of fluid to and from said sealing means so that the sealing means may be deflated to open said passage and said gap.

21. An apparatus as set forth in claim 20, wherein said coupling means comprises annular flange means provided on said supply conduit means, an annular housing element rigid with said shaft and comprising a portion defining an annular clearance with said flange means, and a supply of mercury in said housing element whereby, when said housing element rotates with said shaft, the mercury fills said clearance and seals the interior of said shaft from the atmosphere.

22. A centrifugal apparatus for separating extracted sugar juice into a solid and a liquid fraction, comprising a rotary housing defining an annular compartment including an outer zone distant from the axis thereof, said housing further defining an annular washing chamber surrounding said outer zone, passage means communicatively connecting said outer zone with said chamber, inlet means through which the junce is admitted at elevated pressure into said compartment, and outlet means through which the liquid fraction is evacuated from said compartment when the housing rotates; sealing means for selectively closing and opening said passage means; and means for admitting a hydraulic Washing fluid into said chamber, the area of said passage means in the open position thereof being such that the solid fraction which accumulates in said outer zone in response to rotation of the housing is rapidly diluted by contact with the fluid and penetrates into said chamber to expel corresponding quantities of fluid into said compartment when said sealing means opens said passage means whereby the fluid Washes the solid fraction and entrains into said compartment at least some of the liquid fraction which might have been entrapped in the undiluted solid fraction.

References Cited in the file of this patent UNITED STATES PATENTS 671,573 Wielgolaski Apr. 9, 1901 1,735,692 Nyrop Nov. 12, 1929 2,880,929 Podbielniak Apr. 7, 1959 3,027,390 Thurman Mar. 27, 1962 FOREIGN PATENTS 1,057,535 Germany May 14, 1959 

1. A CENTRIFUGAL APPARATUS FOR SEPARATING A SUSPENSION INTO A SOLID AND A LIQUID COMPONENT, PARTICULARLY FOR SEPAHAVING AN ANNULAR SOLIDS-COLLECTING COMPARTMENT, AN ANNULAR WASHING CHAMBER SURROUNDING SAID COMPARTMENT, AND PASSAGE MEANS COMMUNICATIVELY CONNECTING SAID COMPARTMENT WITH SAID CHAMBER; SEALING MEANS FOR SELECTIVELY CLOSING AND OPENING SAID PASSAGE MEANS SO THAT THE SOLID COMPONENT SEPARATED FROM A SUSPENSION INTRODUCED INTO SAID COMPARTMENT AT ELEVATED PRESSURE IS FREE TO PASS INTO SAID CHAMBER WHEN THE PASSAGE MEANS IS OPEN AND THE HOUSING ROTATES; AND MEANS FOR ADMITTING A HYDRAULIC WASHING FLUID INTO SAID CHAMBER, THE AREA OF SAID PASSAGE MEANS IN OPEN POSITION THEREOF BEING SUCH THAT THE SOLID COMPONENT IS RAPIDLY DILUTED BY THE WASHING FLUID AND PENETRATES INTO SAIDCHAMBER SO AS TO EXPEL CORRESPONDING QUANTITIES OF WASHING FLUID FROMSAID CHAMBER INTO SAID COMPARTMENT WHEN SAID PASSAGE MEANS IS OPEN WHEREBY THE FLUID WASHES THE SOLID COMPONENT WHILE PASSING FROM SAID CHAMBER AND ENTRAINS ITO SAID COMPARTMENT AT LEAST SOME OF THE LIQUID COMPONENT WHICH MIGHT HAVE BEEN ENTRAPPED IN THE UNDILUTED SOLID COMPONENT. 